Re: [PATCH] ALSA: usb-audio: Add quirk for Focusrite Scarlett 2i2

[Alexander Tsoy]

Ð ÐÐ, 20/04/2020 Ð 22:19 +0200, Gregor Pintar ÐÐÑÐÑ:
> Force it to use asynchronous playback.

Can we use snd_usb_audioformat_attributes_quirk() for such fixes? See
the quirk for Griffin iMic as an example.

> 
> Same quirk has already been added for Focusrite Scarlett Solo (2nd
> gen)
> with a commit 46f5710f0b88 ("ALSA: usb-audio: Add quirk for Focusrite
> Scarlett Solo").
> 
> This also seems to prevent regular clicks when playing at 44100Hz
> on Scarlett 2i2 (2nd gen). I did not notice any side effects.
> 
> Signed-off-by: Gregor Pintar <grpintar@xxxxxxxxx>
> ---
>  sound/usb/quirks-table.h | 84
> ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 84 insertions(+)
> 
> diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
> index e009d584e..bc936bf79 100644
> --- a/sound/usb/quirks-table.h
> +++ b/sound/usb/quirks-table.h
> @@ -2840,6 +2840,90 @@ YAMAHA_DEVICE(0x7010, "UB99"),
>  		}
>  	}
>  },
> +{
> +	/*
> +	 * Focusrite Scarlett 2i2 2nd generation
> +	 * Reports that playback should use Synch: Synchronous
> +	 * while still providing a feedback endpoint. Synchronous
> causes
> +	 * snapping on some sample rates.
> +	 * Force it to use Synch: Asynchronous.
> +	 */
> +	USB_DEVICE(0x1235, 0x8202),
> +	.driver_info = (unsigned long) &(const struct
> snd_usb_audio_quirk) {
> +		.ifnum = QUIRK_ANY_INTERFACE,
> +		.type = QUIRK_COMPOSITE,
> +		.data = (const struct snd_usb_audio_quirk[]) {
> +			{
> +				.ifnum = 1,
> +				.type = QUIRK_AUDIO_FIXED_ENDPOINT,
> +				.data = &(const struct audioformat) {
> +					.formats =
> SNDRV_PCM_FMTBIT_S32_LE,
> +					.channels = 2,
> +					.iface = 1,
> +					.altsetting = 1,
> +					.altset_idx = 1,
> +					.attributes = 0,
> +					.endpoint = 0x01,
> +					.ep_attr =
> USB_ENDPOINT_XFER_ISOC |
> +						USB_ENDPOINT_SYNC_ASYNC
> ,
> +					.protocol = UAC_VERSION_2,
> +					.rates = SNDRV_PCM_RATE_44100 |
> +						SNDRV_PCM_RATE_48000 |
> +						SNDRV_PCM_RATE_88200 |
> +						SNDRV_PCM_RATE_96000 |
> +						SNDRV_PCM_RATE_176400 |
> +						SNDRV_PCM_RATE_192000,
> +					.rate_min = 44100,
> +					.rate_max = 192000,
> +					.nr_rates = 6,
> +					.rate_table = (unsigned int[])
> {
> +						44100, 48000, 88200,
> +						96000, 176400, 192000
> +					},
> +					.clock = 41
> +				}
> +			},
> +			{
> +				.ifnum = 2,
> +				.type = QUIRK_AUDIO_FIXED_ENDPOINT,
> +				.data = &(const struct audioformat) {
> +					.formats =
> SNDRV_PCM_FMTBIT_S32_LE,
> +					.channels = 2,
> +					.iface = 2,
> +					.altsetting = 1,
> +					.altset_idx = 1,
> +					.attributes = 0,
> +					.endpoint = 0x82,
> +					.ep_attr =
> USB_ENDPOINT_XFER_ISOC |
> +						USB_ENDPOINT_SYNC_ASYNC
> |
> +						USB_ENDPOINT_USAGE_IMPL
> ICIT_FB,
> +					.protocol = UAC_VERSION_2,
> +					.rates = SNDRV_PCM_RATE_44100 |
> +						SNDRV_PCM_RATE_48000 |
> +						SNDRV_PCM_RATE_88200 |
> +						SNDRV_PCM_RATE_96000 |
> +						SNDRV_PCM_RATE_176400 |
> +						SNDRV_PCM_RATE_192000,
> +					.rate_min = 44100,
> +					.rate_max = 192000,
> +					.nr_rates = 6,
> +					.rate_table = (unsigned int[])
> {
> +						44100, 48000, 88200,
> +						96000, 176400, 192000
> +					},
> +					.clock = 41
> +				}
> +			},
> +			{
> +				.ifnum = 3,
> +				.type = QUIRK_IGNORE_INTERFACE
> +			},
> +			{
> +				.ifnum = -1
> +			}
> +		}
> +	}
> +},
>  
>  /* Access Music devices */
>  {